JPH0723675Y2 - Electric fusing cap - Google Patents

Description

[Detailed description of the device]

[0001]

[Industrial applications]

The present invention relates to an electrofusion cap suitable for closing an end of a piped polyethylene pipe, for example.

[0002]

[Prior art]

Conventionally, with regard to a cap that closes a plastic pipe, the inner surface of the cap made of a thermoplastic resin and the outer surface of the polyethylene pipe are heated with a hot plate, and when the temperature rises to an appropriate temperature, they are inserted into each other and fusion-bonded. Was there.

As an electric fusion type pipe joint, for example, there is an electric fusion socket disclosed in Japanese Patent Publication No. 61-41292. This is a heating wire embedded in a spiral shape on the inner surface of the joint and connected to connector pins at both ends of the joint.A current is applied to this connector pin to heat the heating wire, and the polyethylene pipe The outer surface and the inner surface of the joint are fused and fusion-bonded to each other.

[0004]

[Problems to be solved by the device]

The former of the above prior arts has a problem that the heating temperature on the hot plate is not constantly heated, resulting in defective fusion and incomplete connection.

The latter is an excellent socket for connecting polyethylene pipes because the fusion splicing is completely performed. However, a socket method in which this heating wire is spirally wound and connected to the connector pins at both ends of the joint is adopted. However, when it is applied to a cap joint that closes the pipe end, connector pins must be provided on the opening side and the closing side of the cap, and the workability is poor.
When a pair of connector pins are to be provided on the opening side of the cap, as shown in FIGS. 3 and 4, the end of the heating wire wound from the opening side to the closing side is placed on the heating wire wound. Since it has to be traversed back to the opening side and connected to the other connector pin, there is a risk of a short circuit short between the wound heating wire and the heating wire of the crossing part during fusion splicing work. . If a short circuit occurs in the heating wire, heating will not be performed uniformly and normal fusion splicing will not be performed.

The present invention solves the above problems, and provides an electric fusion-bonding cap in which short-circuiting of heating wires does not occur and two connector pins are arranged at the end portion on the opening side for easy connection.

[0007]

[Means for Solving the Problems]

The gist of the present invention is to provide an electrofusion cap made of a thermoplastic resin that is melted and connected to the outer surface of a thermoplastic resin tube to close the end of the tube. An inner cylinder provided with two spiral grooves on the outer peripheral surface and a projection for locking the heating wire on the outer surface on the closed side, and two end pieces that are bent back by engaging with the projection of the inner cylinder. A heating wire wound in a spiral groove and mounted, a pair of connector pins fixed to the outer surface of the opening side end of the inner cylinder and connected to each end of the heating wire, and a resin injected to the outer surface of the inner cylinder. An electric fusion-bonding cap, comprising: an outer cylinder that is molded and integrally formed with an inner cylinder, has a connector pin protruding to the outer surface, and has heating wires embedded therein.

[0008]

[Action]

Since the present invention has the above-mentioned configuration, the heating wire is wound around one spiral groove in the two spiral grooves provided on the outer surface of the cylindrical body to engage the connector pin on the opening side to the protrusion on the closing side and further to the protrusion. It is stopped and folded back, wound around the other spiral groove, and connected to the connector pin on the opening side. Therefore, even if a pair of connector pins are provided on the opening end side of the cap, there is no portion where the heating wires are overlapped with each other.
When forming the outer cylinder on the outer surface of the inner cylinder by injection molding, or during connection work, there is no problem that the resin melts and the heating wires short-circuit, and there is a pair of connector pins on the open end side. Good workability when connecting.

[0009]

【Example】

1 and 2 are views showing an embodiment of the present invention. In FIG. 1, a heating wire 15 is wound on an inner cylinder 1 in a state that a cross-sectional view is shown in an upper half thereof and an outer cylinder 2 is removed from a lower half thereof. FIG. 2 shows a plan view in a rotated state, and FIG. 2 shows a side view of the inner cylinder 1 without the outer cylinder 2. The inner cylinder 1 is a thin-walled cylindrical body made of the same thermoplastic resin as that of the resin pipe to be connected, one of which is open and the other is closed. The spiral groove 13 of the strip is provided, and the projection 14 is provided on the outer surface of the closing side.

Connector pins 12 and 12 ′ are inserted and fixed in the recessed holes 11, and the heating wire 15 has one end of one of the connector pins 12
It is connected to and wound in one of the two spiral grooves 13, locked by a protrusion 14 provided on the outer surface on the closed side and bent back, and wound in the other spiral groove 13 and fixed to the opening side. Connector pin
It is connected to 12 '.

In this way, the heating wire 15 is attached to the spiral groove 13 of the inner cylinder 1 and the pair of connector pins 12 and 12 ′ is fixed to the opening side and connected to the ends of the heating wire. On the outer surface of the state shown,
The outer cylinder 2 is formed by injection molding a thermoplastic resin. The connector pins 12 and 12 'fixed to the inner cylinder 1 are the outer cylinder 2
Is projected to the outer surface, and a current is applied from an external power source. A temperature measuring hole 21 is provided near the connector pins 12 and 12 ', and a thermocouple thermometer is inserted into the temperature measuring hole 21 from the outside to the vicinity of the heating wire 15 and the temperature of the fusion part at the time of fusion splicing. Is detected. The power supply is controlled so as to turn off when the detected temperature reaches a certain temperature.

As described above, the heating wire 15 is locked to the projection 15 and has two spiral grooves.
Since it is wound inside 13 and connected to connector pins 12 and 12 ', there are no overlapping parts of the heating wires, so the outer tube 2
There is no problem of short-circuiting when forming by injection molding or during fusion splicing work, and fusion splicing can be performed reliably.

[0013]

[Effect of device]

As described above, the electric fusion cap of the present invention has no fear of causing a short circuit during the fusion splicing work, and the splicing work can be easily performed.

[Brief description of drawings]

1 and 2 are views showing an embodiment of the present invention. FIG. 1 is a cross-sectional view in the upper half thereof and an inner cylinder 1 excluding the outer cylinder 2 in the lower half thereof.
A plan view of the heating wire 15 wound around is shown. FIG. 2 shows a side view of the inner cylinder 1 without the outer cylinder 2. 3 and 4 show a conventional example, and FIG. 3 is a plan view showing a state in which a heating wire is wound around an inner cylinder 1 excluding an outer cylinder 2 in a lower half of the drawing and an upper half thereof. Indicates. FIG. 4 shows a side view of the inner cylinder 1 without the outer cylinder 2 of FIG.

[Explanation of symbols]

 1 …… Inner cylinder, 2 …… Outer cylinder 11 …… Concave hole, 12 …… Connector pin 13 …… Two spiral grooves, 14 …… Protrusion 15 …… Heating wire

Front page continued (72) Inventor Nobuhiro Nishikata No. 2 Daifuku, Kuwana City, Mie Prefecture Inside the Kuwana Plant, Hitachi Metals Co., Ltd. (56) References JP 64-74383 (JP, A) JP 63-111394 (JP) , A) Japanese Patent Publication Sho 61-41292 (JP, B2)

Claims (1)

[Scope of utility model registration request] 1. An electric fusion cap made of a thermoplastic resin for closing a pipe end by fusion-connecting to an outer surface of a thermoplastic resin pipe, wherein an outer periphery of a thin-walled cylinder whose one end forming an inner shape of the cap is closed. An inner cylinder having two spiral grooves on its surface and a projection for locking a heating wire on the outer surface on the closed side, and two spirals for each end bent and locked by the projection of the inner cylinder. A heating wire wound around and mounted in the groove, a pair of connector pins fixed to the outer surface of the opening side end of the inner cylinder and connected to each end of the heating wire, and a resin injection-molded on the outer surface of the inner cylinder. And an outer cylinder in which the connector pins are protruded to the outer surface and the heating wire is embedded, and an electric fusion-bonding cap.